The birthday cake is traditionally highly decorated, and typically covered with lit candles when presented, the number of candles signifying the age of the celebrant. The person whose birthday it is may make a silent wish and then blow out the candles. After that, the person can open their presents. It is also common for the person celebrating their birthday to cut the initial piece of the cake as a newlywed couple might with a wedding cake.

Birthday cakes date back as far as the Middle Ages when the English would conceal symbolic items such as gold coins, rings and thimbles inside their cakes.^{[citation needed]} Each item was associated with a prediction. For example, a person finding a gold coin in a birthday cake would supposedly become wealthy; a person discovering a thimble would never marry.

Sometimes special candles are substituted for the many individual candles in the shape of a numeral. For example, on the fifth birthday, there may be one candle on the cake in the shape of the numeral five, and on the fiftieth birthday there may be two candles on the cake, one in the shape of the numeral five followed by the other in the shape of the number zero.

from Wikipedia.com/Birthday